We report a modified chirally-coupled-core (3C) fiber with a large-diameter, low-numerical-aperture (NA) side-core design, inspired by our observation that quasi-phase-matching resonance critically depends on the side-core mode order and diameter. In particular, resonance with the side-core LP11 mode enables efficient high-order mode (HOM) leakage while preserving low fundamental-mode (FM) loss in the central core. The designed fiber can achieve a minimum FM loss of 0.08 dB/m, while maintaining high HOM loss (>10 dB/m) for the LP11 group, and offers a broad operating window of 300 nm, significantly outperforming conventional circular-core 3C fibers. With optimized bending, the fiber can sustain heat loads up to 120 W/m. The design is also scalable: introducing additional large-diameter side-cores allows the central-core diameter to be increased up to 50 μm while preserving effective HOM suppression and low FM loss. This work provides insights into the mechanistic and structural behavior of 3C fibers and proposes an optimized fiber design suitable for high-power laser amplification and transmission applications.
{"title":"Low loss, broad bandwidth and good heat load tolerance in a modified chirally-coupled-core fiber with large-diameter and low-NA side-core design","authors":"Yifeng Hong, Jianchang Tan, He Hao, Jiabin Bai, Zupei Zhan, Dong Li, Shuiliang Zhou","doi":"10.1016/j.optcom.2026.132981","DOIUrl":"10.1016/j.optcom.2026.132981","url":null,"abstract":"<div><div>We report a modified chirally-coupled-core (3C) fiber with a large-diameter, low-numerical-aperture (NA) side-core design, inspired by our observation that quasi-phase-matching resonance critically depends on the side-core mode order and diameter. In particular, resonance with the side-core LP<sub>11</sub> mode enables efficient high-order mode (HOM) leakage while preserving low fundamental-mode (FM) loss in the central core. The designed fiber can achieve a minimum FM loss of 0.08 dB/m, while maintaining high HOM loss (>10 dB/m) for the LP<sub>11</sub> group, and offers a broad operating window of 300 nm, significantly outperforming conventional circular-core 3C fibers. With optimized bending, the fiber can sustain heat loads up to 120 W/m. The design is also scalable: introducing additional large-diameter side-cores allows the central-core diameter to be increased up to 50 μm while preserving effective HOM suppression and low FM loss. This work provides insights into the mechanistic and structural behavior of 3C fibers and proposes an optimized fiber design suitable for high-power laser amplification and transmission applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132981"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-02-06DOI: 10.1016/j.optcom.2026.133001
Yiwen Zhang, Wenhui Ma, Yamin Huang, Xuezhi Hong
Probabilistic constellation shaping (PCS) enables rate-adaptive optical transmission in elastic optical networks, but accurate identification of the shaping distribution (SD) at the receiver remains challenging under complex channel conditions. We propose a novel phase-insensitive SD identification (SDI) method using exact likelihood evaluation with score-based generative models (SGMs). In this approach, an SGM is trained for each candidate SD using higher-order denoising score matching to learn the probability density of the received signal's radius via an ordinary differential equation equivalent diffusion process. SDI is then performed by computing the Kullback–Leibler divergence between the actual received signal distribution and the a priori distributions learned by the SGMs. Simulations in optical back-to-back (BTB) and long-haul fiber scenarios show that our data-driven method significantly outperforms the previous unsupervised phase-insensitive approach R-EM. In BTB, it achieves success rates of 95.3 % (N = 2048) and 98.8 % (N = 4096) at a normalized generalized mutual information (NGMI) of 0.9, with gains of 11.3 % and 11.1 % over R-EM. In fiber transmission, SGMs trained on BTB data generalize well to various distances, improving accuracy by ∼9 % over R-EM. Additionally, under modulator and fiber nonlinearities, our method offers ∼5-8 % higher accuracy than R-EM, demonstrating its superior resilience to nonlinear effects.
{"title":"Phase-insensitive shaping distribution identification in rate-adaptive PCS-MQAM optical transmission systems via exact likelihood evaluation with score-based generative models","authors":"Yiwen Zhang, Wenhui Ma, Yamin Huang, Xuezhi Hong","doi":"10.1016/j.optcom.2026.133001","DOIUrl":"10.1016/j.optcom.2026.133001","url":null,"abstract":"<div><div>Probabilistic constellation shaping (PCS) enables rate-adaptive optical transmission in elastic optical networks, but accurate identification of the shaping distribution (SD) at the receiver remains challenging under complex channel conditions. We propose a novel phase-insensitive SD identification (SDI) method using exact likelihood evaluation with score-based generative models (SGMs). In this approach, an SGM is trained for each candidate SD using higher-order denoising score matching to learn the probability density of the received signal's radius via an ordinary differential equation equivalent diffusion process. SDI is then performed by computing the Kullback–Leibler divergence between the actual received signal distribution and the <em>a priori</em> distributions learned by the SGMs. Simulations in optical back-to-back (BTB) and long-haul fiber scenarios show that our data-driven method significantly outperforms the previous unsupervised phase-insensitive approach R-EM. In BTB, it achieves success rates of 95.3 % (N = 2048) and 98.8 % (N = 4096) at a normalized generalized mutual information (NGMI) of 0.9, with gains of 11.3 % and 11.1 % over R-EM. In fiber transmission, SGMs trained on BTB data generalize well to various distances, improving accuracy by ∼9 % over R-EM. Additionally, under modulator and fiber nonlinearities, our method offers ∼5-8 % higher accuracy than R-EM, demonstrating its superior resilience to nonlinear effects.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 133001"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-02-05DOI: 10.1016/j.optcom.2026.132988
Ruofan Cai , Feng Zhou , Weining Chen , Hongyan Wang , Yuchen Ge , Qingsheng Xie , Yaohong Chen
Atmospheric turbulence is one of the most devastating degradation factors in long-focus, long-range infrared imaging systems. Most existing turbulence mitigation methods are developed for visible light scenarios, while research targeting infrared scenarios remains scarce. In this paper, we propose a two-stage infrared image enhancement turbulence method, which combines an enhanced Difference of Gaussian (DoG) filtering module and a deep neural network to restore infrared images degraded by atmospheric turbulence. This approach mitigates blurring and geometric distortion caused by atmospheric turbulence and significantly improves the image quality, which is also applicable to moving objects. Experiments on synthetic and real-world turbulence datasets demonstrate the proposed method's strong restoration and enhancement performance, which achieves improvements of 3.7% in Peak Signal-to-Noise Ratio (PSNR) and 2.6% in Structural Similarity Index (SSIM) compared with state-of-the-art methods, with a processing rate of approximately 27 fps for 640 × 512 short-wave infrared images.
{"title":"A two-stage framework for infrared image enhancement under long-range turbulence","authors":"Ruofan Cai , Feng Zhou , Weining Chen , Hongyan Wang , Yuchen Ge , Qingsheng Xie , Yaohong Chen","doi":"10.1016/j.optcom.2026.132988","DOIUrl":"10.1016/j.optcom.2026.132988","url":null,"abstract":"<div><div>Atmospheric turbulence is one of the most devastating degradation factors in long-focus, long-range infrared imaging systems. Most existing turbulence mitigation methods are developed for visible light scenarios, while research targeting infrared scenarios remains scarce. In this paper, we propose a two-stage infrared image enhancement turbulence method, which combines an enhanced Difference of Gaussian (DoG) filtering module and a deep neural network to restore infrared images degraded by atmospheric turbulence. This approach mitigates blurring and geometric distortion caused by atmospheric turbulence and significantly improves the image quality, which is also applicable to moving objects. Experiments on synthetic and real-world turbulence datasets demonstrate the proposed method's strong restoration and enhancement performance, which achieves improvements of 3.7% in Peak Signal-to-Noise Ratio (PSNR) and 2.6% in Structural Similarity Index (SSIM) compared with state-of-the-art methods, with a processing rate of approximately 27 fps for 640 × 512 short-wave infrared images.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132988"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel non-diffracting beam, ‘the Vector Tricomi beam’, is introduced as an exact solution to the vector Helmholtz wave equation. Its unique mathematical structure allows for its transformation into other vector beams, such as ordinary, off-axis, and asymmetric Bessel beams, by adjusting its intrinsic parameters. A detailed mathematical analysis of the beam’s intensity, polarization, singularities, and Stokes parameters is performed. The analysis reveals that the beam’s asymmetry significantly influences its intensity and polarization, creating unique polarization distributions with distinct spin angular momentum and singularity. Unlike scalar Tricomi beams, these vector beams are suitable for polarization multiplexing, enabling the generation of numerous beams with different parameters under the same mode number. A hybrid polarization-asymmetry multiplexing technique is discussed, highlighting the potential of these beams for advanced data storage and multiplexing applications.
{"title":"Non-diffracting Vector Tricomi beams","authors":"Sumit Kumar Singh , Kenji Kinashi , Naoto Tsutsumi , Yasuhiro Awatsuji , Boaz Jessie Jackin","doi":"10.1016/j.optcom.2026.133004","DOIUrl":"10.1016/j.optcom.2026.133004","url":null,"abstract":"<div><div>A novel non-diffracting beam, ‘the Vector Tricomi beam’, is introduced as an exact solution to the vector Helmholtz wave equation. Its unique mathematical structure allows for its transformation into other vector beams, such as ordinary, off-axis, and asymmetric Bessel beams, by adjusting its intrinsic parameters. A detailed mathematical analysis of the beam’s intensity, polarization, singularities, and Stokes parameters is performed. The analysis reveals that the beam’s asymmetry significantly influences its intensity and polarization, creating unique polarization distributions with distinct spin angular momentum and singularity. Unlike scalar Tricomi beams, these vector beams are suitable for polarization multiplexing, enabling the generation of numerous beams with different parameters under the same mode number. A hybrid polarization-asymmetry multiplexing technique is discussed, highlighting the potential of these beams for advanced data storage and multiplexing applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 133004"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-29DOI: 10.1016/j.optcom.2026.132959
Haiming Lu , Geyou Zhang , Rui Gao , Tong Zhou , Bo Zhang , Bin Xu , Kai Liu
One-shot structured light enables real-time 3D scanning, while typically suffering from poor accuracy. In fringe projection profilometry, phase sensitivity is maximized when the phase variation direction is orthogonal to the epipolar lines of the projector. Straight fringes are quasi-optimal under certain conditions. However, they are sensitive to system setup, and misalignment can cause noticeable accuracy loss. Circular fringe patterns overcome this limitation by achieving globally optimal phase sensitivity. In this paper, we present a generalized framework for one-shot FPP using optimal circular fringes. First, we develop a filter based on geometric analysis of the spectrum to extract the wrapped phase. Second, phase unwrapping and mapping are conducted to restore absolute phase. Finally we reconstruct 3D points via the extended epipolar geometry. Experiments show that circular fringes significantly improve reconstruction accuracy, especially in fine details, highlighting their superiority over straight fringes.
{"title":"One-shot optimal circular fringe projection profilometry","authors":"Haiming Lu , Geyou Zhang , Rui Gao , Tong Zhou , Bo Zhang , Bin Xu , Kai Liu","doi":"10.1016/j.optcom.2026.132959","DOIUrl":"10.1016/j.optcom.2026.132959","url":null,"abstract":"<div><div>One-shot structured light enables real-time 3D scanning, while typically suffering from poor accuracy. In fringe projection profilometry, phase sensitivity is maximized when the phase variation direction is orthogonal to the epipolar lines of the projector. Straight fringes are quasi-optimal under certain conditions. However, they are sensitive to system setup, and misalignment can cause noticeable accuracy loss. Circular fringe patterns overcome this limitation by achieving globally optimal phase sensitivity. In this paper, we present a generalized framework for one-shot FPP using optimal circular fringes. First, we develop a filter based on geometric analysis of the spectrum to extract the wrapped phase. Second, phase unwrapping and mapping are conducted to restore absolute phase. Finally we reconstruct 3D points via the extended epipolar geometry. Experiments show that circular fringes significantly improve reconstruction accuracy, especially in fine details, highlighting their superiority over straight fringes.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132959"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-02-03DOI: 10.1016/j.optcom.2026.132984
Gyaprasad , Rajneesh Joshi
We theoretically investigate a novel mechanism for controlling the quantum degree of polarization of single- and multi-photon light fields through the combined effects of birefringence and dispersion in optical media. While birefringence alone introduces a unitary phase shift between horizontal (H) and vertical (V) polarization modes, the inclusion of dispersion produces frequency-dependent effects that couple polarization with spectral degrees of freedom, thereby inducing decoherence and transforming the quantum state into a mixed state. By employing an electro-optically controlled nematic liquid crystal as the birefringent medium, this decoherence process can be harnessed to achieve tunable control of the quantum degree of polarization. We model this voltage-dependent tunability theoretically and propose methods for experimental verification.
{"title":"Tunable decoherence of quantum polarization states via birefringence-frequency coupling using liquid crystal","authors":"Gyaprasad , Rajneesh Joshi","doi":"10.1016/j.optcom.2026.132984","DOIUrl":"10.1016/j.optcom.2026.132984","url":null,"abstract":"<div><div>We theoretically investigate a novel mechanism for controlling the quantum degree of polarization of single- and multi-photon light fields through the combined effects of birefringence and dispersion in optical media. While birefringence alone introduces a unitary phase shift between horizontal (H) and vertical (V) polarization modes, the inclusion of dispersion produces frequency-dependent effects that couple polarization with spectral degrees of freedom, thereby inducing decoherence and transforming the quantum state into a mixed state. By employing an electro-optically controlled nematic liquid crystal as the birefringent medium, this decoherence process can be harnessed to achieve tunable control of the quantum degree of polarization. We model this voltage-dependent tunability theoretically and propose methods for experimental verification.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132984"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compared to traditional sensors, metasurface sensors offer higher sensitivity and superior optical response. All-dielectric materials have broad prospects for refractive index sensing due to low ohmic loss. Here, we propose a double-rod all-dielectric nanostructure that exhibits a high-quality factor (high-Q) Fano resonance in the mid-infrared band. This resonance is highly sensitive to changes in the refractive index of the surrounding medium. Analysis of the electromagnetic field distribution and multipole moment decomposition, it is demonstrated that the resonance is driven by a toroidal dipole (TD) and a magnetic quadrupole (MQ). We systematically characterized the sensing performance of the proposed structure. The results show that it achieves a sensitivity of up to 1337.1 nm/RIU and a high figure of merit (FOM) of 1238. In the mid-infrared band, the structure exhibited a high Q factor of 18544. Moreover, its reflection spectrum in this band could be effectively tuned by adjusting the geometric parameters of the metasurface. Finally, investigations at different incident angles reveal that the resonant peak exhibits a distinct blueshift as the angle increases. Moreover, the structure shows a selective response to the polarization state, demonstrating excellent polarization sensitivity. This work shows that high-performance optical sensors can be fabricated using simple processes, thereby providing a fresh design framework and theoretical basis for the sensor community.
{"title":"High-Q mid-infrared refractive index sensor based on Fano resonance in an all-dielectric double-rod structure","authors":"Wenwen Wang, Fuming Yang, Wenwen Sun, Zhe Wu, Xiaoyan Shi, Junying Liu, Yuetao Liu, Jizheng Geng, Xintong Wei, Xiangtao Chen, Shijia Zhu, Zhongzhu Liang","doi":"10.1016/j.optcom.2026.132975","DOIUrl":"10.1016/j.optcom.2026.132975","url":null,"abstract":"<div><div>Compared to traditional sensors, metasurface sensors offer higher sensitivity and superior optical response. All-dielectric materials have broad prospects for refractive index sensing due to low ohmic loss. Here, we propose a double-rod all-dielectric nanostructure that exhibits a high-quality factor (high-Q) Fano resonance in the mid-infrared band. This resonance is highly sensitive to changes in the refractive index of the surrounding medium. Analysis of the electromagnetic field distribution and multipole moment decomposition, it is demonstrated that the resonance is driven by a toroidal dipole (TD) and a magnetic quadrupole (MQ). We systematically characterized the sensing performance of the proposed structure. The results show that it achieves a sensitivity of up to 1337.1 nm/RIU and a high figure of merit (FOM) of 1238. In the mid-infrared band, the structure exhibited a high Q factor of 18544. Moreover, its reflection spectrum in this band could be effectively tuned by adjusting the geometric parameters of the metasurface. Finally, investigations at different incident angles reveal that the resonant peak exhibits a distinct blueshift as the angle increases. Moreover, the structure shows a selective response to the polarization state, demonstrating excellent polarization sensitivity. This work shows that high-performance optical sensors can be fabricated using simple processes, thereby providing a fresh design framework and theoretical basis for the sensor community.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132975"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-02-03DOI: 10.1016/j.optcom.2026.132989
Jing Cui , Chao Wang , Yingchao Li , Qiang Fu , Xiangyu Li , Jianan Liu
The two-dimensional area imaging characteristics of the lenslet array IFS cause the incident light to possess a two-dimensional spatial distribution at the grating. This thereby leads to multi-order spectral overlap. Conventional spectral overlap suppression methods designed for slit-based imaging spectrometers with a single field of view are inadequate to address this issue directly, resulting in a significantly increased risk of spectral overlap and reduced accuracy of the acquired spectral data. To address this, this paper proposes a multi-order spectral overlap suppression method. Its core lies in establishing a constraint relationship among the maximum angle between the incident light and the grating normal, the spectral range, and the grating spacing. Based on this, strict conditions are derived to ensure that no spectral overlap occurs between zero-order and first-order, or between first-order and second-order spectra across all fields of view within the target wavelength band, thereby achieving effective suppression of spectral overlap during the initial design stage. Building upon these constraint conditions, a coordinated selection method for the grating spacing, the focal length of the collimation system, and the focal length of the imaging system is further proposed. To validate the effectiveness of the proposed method, a lenslet array IFS with a field of view of and an operational wavelength range of 550-800 nm was designed. The design results indicate that on the detector focal plane, a clear separation exists between the first-order diffracted spectrum of incident light 1 at long wavelengths and the second-order diffracted spectrum of incident light 2 at short wavelengths, while the zero-order spot is completely isolated from the first-order spectrum. This achieves full-band crosstalk-free operation and significantly improves the accuracy of spectral information.
{"title":"Research and design of multi-order spectral overlap suppression in a lenslet array integral field spectrometer (IFS)","authors":"Jing Cui , Chao Wang , Yingchao Li , Qiang Fu , Xiangyu Li , Jianan Liu","doi":"10.1016/j.optcom.2026.132989","DOIUrl":"10.1016/j.optcom.2026.132989","url":null,"abstract":"<div><div>The two-dimensional area imaging characteristics of the lenslet array IFS cause the incident light to possess a two-dimensional spatial distribution at the grating. This thereby leads to multi-order spectral overlap. Conventional spectral overlap suppression methods designed for slit-based imaging spectrometers with a single field of view are inadequate to address this issue directly, resulting in a significantly increased risk of spectral overlap and reduced accuracy of the acquired spectral data. To address this, this paper proposes a multi-order spectral overlap suppression method. Its core lies in establishing a constraint relationship among the maximum angle between the incident light and the grating normal, the spectral range, and the grating spacing. Based on this, strict conditions are derived to ensure that no spectral overlap occurs between zero-order and first-order, or between first-order and second-order spectra across all fields of view within the target wavelength band, thereby achieving effective suppression of spectral overlap during the initial design stage. Building upon these constraint conditions, a coordinated selection method for the grating spacing, the focal length of the collimation system, and the focal length of the imaging system is further proposed. To validate the effectiveness of the proposed method, a lenslet array IFS with a field of view of <span><math><mrow><mo>±</mo><msup><mn>4.76</mn><mo>∘</mo></msup></mrow></math></span> and an operational wavelength range of 550-800 nm was designed. The design results indicate that on the detector focal plane, a clear separation exists between the first-order diffracted spectrum of incident light 1 at long wavelengths and the second-order diffracted spectrum of incident light 2 at short wavelengths, while the zero-order spot is completely isolated from the first-order spectrum. This achieves full-band crosstalk-free operation and significantly improves the accuracy of spectral information.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132989"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-31DOI: 10.1016/j.optcom.2026.132983
Wei Wei , Ruitao Wu , Zaiqun Wu , Juncheng Fang , Ying Li , Ting Lei , Xiaocong Yuan
The non-equalization property of mode-dependent loss (MDL) fundamentally limits the information capacities of mode-division multiplexing (MDM) systems, particularly for long-distance optical communications. We propose an inverse-designed approach for MDM systems with low MDL by integrating the mode-dependent equalizer into the multi-plane light conversion (MPLC) component for multi-mode wavefront matching. We experimentally demonstrate a six-mode free-space MDM link comprising a few-mode fiber and a standard multimode collimator, achieving a uniform loss spectrum with insertion loss lower than −6.62 dB, total mode crosstalk below −20 dB, and mode purity up to 80%. Additionally, each LP modes carrying 20 Gbit/s on-off keying signals are successfully transmitted over a 50-km FMF. We anticipate that this design strategy can be extended to other free-space optical communications systems without additional apparatus, potentially improving information capacity by orders of magnitude.
{"title":"Balanced amplification of six LP modes in 50 km few-mode fiber via multi-plane light conversion","authors":"Wei Wei , Ruitao Wu , Zaiqun Wu , Juncheng Fang , Ying Li , Ting Lei , Xiaocong Yuan","doi":"10.1016/j.optcom.2026.132983","DOIUrl":"10.1016/j.optcom.2026.132983","url":null,"abstract":"<div><div>The non-equalization property of mode-dependent loss (MDL) fundamentally limits the information capacities of mode-division multiplexing (MDM) systems, particularly for long-distance optical communications. We propose an inverse-designed approach for MDM systems with low MDL by integrating the mode-dependent equalizer into the multi-plane light conversion (MPLC) component for multi-mode wavefront matching. We experimentally demonstrate a six-mode free-space MDM link comprising a few-mode fiber and a standard multimode collimator, achieving a uniform loss spectrum with insertion loss lower than −6.62 dB, total mode crosstalk below −20 dB, and mode purity up to 80%. Additionally, each LP modes carrying 20 Gbit/s on-off keying signals are successfully transmitted over a 50-km FMF. We anticipate that this design strategy can be extended to other free-space optical communications systems without additional apparatus, potentially improving information capacity by orders of magnitude.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132983"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-02-04DOI: 10.1016/j.optcom.2026.132990
Muhammad Idrees , Yuanping Chen , Beibing Huang , Hui-Jun Li , Zareen A. Khan , Yuee Xie
We theoretically investigate ultrahigh-resolution two-dimensional (2D) atomic localization in a hybrid nanosystem composed of metallic nanoparticles (MNPs) embedded in a coherent three-level -type atomic medium serving as a dielectric host. Structured laser fields excite tunable surface plasmon polaritons (SPPs) at the MNP-dielectric interface, with resonances analytically derived from Maxwell’s equations under suitable boundary conditions. The atomic dynamics are described via the density matrix formalism, where the control-field Rabi frequency is modeled as a superposition of two orthogonal standing waves along the - and -directions, characterized by azimuthal quantum numbers and spatial phase shifts. The spatially dependent light-matter interaction, together with phase modulation, generates sharply localized probability peaks within a single-wavelength domain, marking high-probability atomic positions. By tuning azimuthal quantum numbers, and the phase parameters, the spatial symmetry is enhanced while the number of localized peaks is reduced, ultimately yielding a single dominant localization site with higher probability. This approach achieves ultrahigh-resolution localization in regions smaller than , representing a significant improvement over previous schemes. The resulting tunable probability distributions provide a versatile platform for precision atomic localization in quantum nanoplasmonics, with potential applications in nanophotonics, nanomedicine, and quantum information processing.
{"title":"Plasmon-enhanced two-dimensional atomic localization with controllable azimuthal symmetry","authors":"Muhammad Idrees , Yuanping Chen , Beibing Huang , Hui-Jun Li , Zareen A. Khan , Yuee Xie","doi":"10.1016/j.optcom.2026.132990","DOIUrl":"10.1016/j.optcom.2026.132990","url":null,"abstract":"<div><div>We theoretically investigate ultrahigh-resolution two-dimensional (2D) atomic localization in a hybrid nanosystem composed of metallic nanoparticles (MNPs) embedded in a coherent three-level <span><math><mi>λ</mi></math></span>-type atomic medium serving as a dielectric host. Structured laser fields excite tunable surface plasmon polaritons (SPPs) at the MNP-dielectric interface, with resonances analytically derived from Maxwell’s equations under suitable boundary conditions. The atomic dynamics are described via the density matrix formalism, where the control-field Rabi frequency is modeled as a superposition of two orthogonal standing waves along the <span><math><mi>x</mi></math></span>- and <span><math><mi>y</mi></math></span>-directions, characterized by azimuthal quantum numbers and spatial phase shifts. The spatially dependent light-matter interaction, together with phase modulation, generates sharply localized probability peaks within a single-wavelength domain, marking high-probability atomic positions. By tuning azimuthal quantum numbers, and the phase parameters, the spatial symmetry is enhanced while the number of localized peaks is reduced, ultimately yielding a single dominant localization site with higher probability. This approach achieves ultrahigh-resolution localization in regions smaller than <span><math><mrow><mi>λ</mi><mo>/</mo><mn>30</mn><mo>×</mo><mi>λ</mi><mo>/</mo><mn>30</mn></mrow></math></span>, representing a significant improvement over previous schemes. The resulting tunable probability distributions provide a versatile platform for precision atomic localization in quantum nanoplasmonics, with potential applications in nanophotonics, nanomedicine, and quantum information processing.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"608 ","pages":"Article 132990"},"PeriodicalIF":2.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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